Blender 2.8: How to see multiple view layers at once in viewport?
According to the blog here: Blender developers blog in 2017


  An exciting future option for the 2.8x roadmap is to use View Layers as compositing units, also for real-time rendering. For simplicity now, we stick to having a single ‘active View Layer’ per Blender window.


And as far as I can see you still have only one active view layer in your blender window at this time.